Power supply and method for compensating low-frequency output voltage ripple thereof

摘要

A power supply has a power factor correction (PFC) circuit and a DC to DC conversion circuit. A DC to DC controller of the DC to DC conversion circuit acquires zero-crossing information and load information from the PFC circuit through a communication protocol, and performs a low-frequency compensation on a control command using a table-mapping means, thereby resolving the issues of higher controller complexity, changes of entire response characteristics and cost increase in conventional compensation technique.

主权项

1. A method for compensating low-frequency output voltage ripple of a power supply, wherein the power supply has a power factor correction (PFC) circuit and a DC (Direct Current) to DC conversion circuit, the DC to DC conversion circuit has a DC to DC controller performing the method, the method comprising steps of:
providing a mapping table with multiple compensation signals built in the DC to DC controller; continuously acquiring zero-crossing information of an AC (Alternating Current) power from the PFC circuit; determining if a zero-crossing of the AC input power is taking place according to the zero-crossing information; and selecting a corresponding compensation signal from the mapping table to compensate a control command when the zero-crossing of the AC input power is taking place.